Weird Things Going on with My Air Conditioning

About a month ago, I had the evaporator replaced in my 2002 Hyundai Accent. Immediately after that, water vapor started blowing out of my vents about 70% of the time I was driving. I took it back to the shop and they said they found water leftover in a hose/drain that they cleared out. This seemed to help A LOT, but now after I drive for 30 minutes, water vapor will come out of the vents and won’t stop until I turn the system off. In addition, after I drive for 30-45 minutes, the air will suddenly decrease significantly in speed (its still super cold, though). I then have to turn the AC to its highest setting for about 2 minutes for the air to come back to normal levels on all settings. In addition, the AC seems to get (dare I say) too cold now and after about 30-45 minutes I have to turn it off for awhile. When I turn it back on, water vapor comes through the vents, but only for about a minute.

I know the car is getting up there in age (it only has 75,000 miles on it), so are these changes normal and something I will just have to put up with, or did my garage mess something up?

Air conditioners have some means to regulate the temperature so they don’t get TOO COLD and ice starts to form in the evaporator coils which will slowly block the air flow…When they replaced your evaporator, they somehow disturbed or disabled this temperature / ice monitoring control…When the Freon is allowed to expand into the evaporator, this flow is controlled by the “expansion valve” or “orifice tube” or an ice sensor that shuts off the compressor and allows the evaporator to warm up a little…